Physics, Biology, and STEM education

Since I’m a physicist who works on biological systems and cares about education, what could be better than a special issue of CBE Life Sciences Education on “Educational Initiatives and Research at the Intersection of Physics and Biology?” (OK, lots of things — I’m not that boring a person — but humor me.)

I’ve read only a small bit of the issue, whose contents are here, but it seems to be full of interesting articles, both on the scientific intersection of physics and biology, and on lessons to be drawn for biology education from the large and impressive corpus of physics education research. The one article I’ve read in its entirety (because it’s short, and because I correctly guessed that it would be thought-provoking) is a cautionary, and even gloomy, essay by Michael Marder called “A Problem with STEM” [Link].

The paper argues that fundamental philosophical differences of opinion as to the nature of science affect how (or whether) the “S” in STEM can really apply to all the sciences, which will affect how we structure and implement improvements in STEM education. The first part of the argument deals with often-taught definitions of words like “law” and “theory” that don’t really apply to much of physics. In the second part, Marder notes that mathematics remains inseparable from education in the physical sciences, but this is not the case in biology. Moreover, an appreciation for the worth of mathematical or theoretical models, even disjoint from experiments, is not generally a part of biological education. None of this is new, and there have certainly been many impassioned calls from people in the biological community for more and better mathematical education. Nonetheless, it’s important to write about, since progress in the area seems so minimal. I am routinely amazed by how many smart biology students I encounter who are not skilled at, or who are even frightened by, undergraduate-level math, and I’m also saddened when this hinders the science they can do.

The third part is most interesting, and deals with “the tyranny of hypotheses.” One of the “cultural” shocks I’ve had moving into biological fields is constantly hearing people talk about “hypotheses” and seeing a steady stream of bar graphs with asterisks and p-values. In physics, one almost never discusses hypotheses; rather, one test relationships between parameters, either analyzing them within some mechanistic framework, or empirically determining what the underlying functional relationship is. The distinction is described with an example (emphasis added):

As an example of a very simple case in which one can see these two modes of science in action, consider constructing an experiment with a light bulb and a light intensity sensor. A biological approach to this system might be to say “My hypothesis is that when the bulb is farther away the light will be dimmer.” This idea would lead to an experiment in which a light bulb is placed at two different locations and intensity is measured multiple times. A low-quality version of the experiment would simply ask which case led to higher mean light intensity, while a higher-quality version would add a t test for significance. Extensions of the experiment could ask whether yellow lights are brighter than green lights.

I have seen biologists nod contentedly at such a description of student-directed scientific progress, but physicists start to squirm. There is no point in checking whether the more distant light bulbs appear dimmer. It is obvious. In fact, with a little geometry, and using the concept of conservation of energy, the student should be able to predict the precise mathematical form of the functional dependence of light intensity upon distance to the sensor. For heaven’s sake, do that, put some error bars on the measurement, and compare it with the expected power law.

Why does this matter? I won’t go into the issue that significance testing is, in practice, very hard to do properly and very easy to do wrong. (This has been well-described in lots of places, which I’m not organized enough to link to, and is a fascinating topic in itself. I’ll just link to an xkcd comic, which is great.) Marder’s point is that indoctrinating students with a hypothesis-testing approach to science, as if that’s how all science is (or should be) done, makes them antagonistic to physics and incapable of adopting or appreciating the quantitative and functional approach to science that physics provides. This, of course, is bad! And so, spelling out the virtues and rewards of “thinking like a physicist” is something we should not neglect.

It’s unfortunate that there’s no picture I can include that’s relevant to this article — this post is a wall of text. I was thinking several days ago of writing about some journal articles discussed at my research group meeting, one of which involved ants, but then I didn’t get around to it. Here’s my illustration of an ant anyway:

One thought on “Physics, Biology, and STEM education”

This is great. As a biologist, I was totally nodding along too with the description of the student research! What a question to explore: how do we as scientists learn to communicate with each other (using a common language) and build on that commonality so we can also talk with students? I am not sure there is an easy answer.